Reinheimer Timo, Mach Tim P, Häuser Kevin, Hoffmann Michael J, Binder Joachim R
Institute for Applied Materials, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany.
Nanomaterials (Basel). 2023 Jan 21;13(3):441. doi: 10.3390/nano13030441.
A detailed study of the dielectric behavior of printed capacitors is given, in which the dielectric consists of a thin (<1 µm) ceramic/polymer composite layer with high permittivities of ε 20-69. The used ink contains surface-modified BaSrTiO (BST), a polymeric crosslinking agent and a thermal initiator, which allows the immediate polymerization of the ink during printing, leading to homogenous layers. To validate the results of the calculated permittivities, different layer thicknesses of the dielectric are printed and the capacitances, as well as the loss factors, are measured. Afterwards, the exact layer thicknesses are determined with cross sectional SEM images of ion-etched samples. Then, the permittivities are calculated with the known effective area of the capacitors. Furthermore, the ink composition is varied to obtain different ceramic/polymer ratios and thus different permittivities. The packing density of all composites is analyzed via SEM to show possible pores and validate the target ratio, respectively. The correlation between the chosen ratio and the measured permittivity is discussed using models from the literature. In addition, the leakage current of some capacitors is measured and discussed. For that, the dielectric was printed on different bottom electrodes as the nature of the electrode was found to be crucial for the performance.
本文对印刷电容器的介电行为进行了详细研究，其中电介质由一层薄（<1 µm）的陶瓷/聚合物复合层组成，其介电常数ε为20 - 69。所使用的油墨包含表面改性的钛酸锶钡（BST）、一种聚合物交联剂和一种热引发剂，这使得油墨在印刷过程中能立即聚合，从而形成均匀的层。为了验证计算介电常数的结果，印刷了不同层厚度的电介质，并测量了电容以及损耗因子。之后，通过离子蚀刻样品的横截面扫描电子显微镜（SEM）图像确定精确的层厚度。然后，利用电容器已知的有效面积计算介电常数。此外，改变油墨成分以获得不同的陶瓷/聚合物比例，从而得到不同的介电常数。通过SEM分析所有复合材料的堆积密度，分别显示可能存在的孔隙并验证目标比例。使用文献中的模型讨论所选比例与测量介电常数之间的相关性。此外，还测量并讨论了一些电容器的漏电流。为此，将电介质印刷在不同的底部电极上，因为发现电极的性质对性能至关重要。
